1. Field of the Invention
The present invention relates to a method of producing packaging containers of plastics, to a packaging container, in particular produced according to said method, a molding station for a plastic packaging container and a packaging machine comprising such a molding station and to a method of producing filled and closed containers.
2. Description of Related Prior Art
So far the production of packaging containers of plastics, in particular for packing foodstuff, has had various disadvantages which have had the effect that efficiently produced plastic packaging containers only exist in a very limited number of shapes and are normally devoid of any reclosing possibilities.
In particular, it has so far only been possible to produce straight-walled, cylindrical or conical cups or containers without any undercuts by deep-drawing, blow-molding or similar processes.
Such containers, however, turn out to be troublesome as to their stability and standing capacity. Moreover, liquid substances, for instance paste-like foodstuff, cannot be filled into such containers at a high speed because the reaction forces always-tend to splash back the packing material during the filling process. Therefore, liquid substances cannot be filled into straight-walled or conical containers at such a high speed as is desired and, in particular, is also possible with containers having undercuts, in which the filling opening has a smaller cross-section than the remaining container cross-section, whereby back splashing or ejection is avoided.
For manufacturing reasons packaging containers which have been made from a plastic film could thus not be provided with shapes that have turned out to be advantageous in the glass or ceramic sector or in the case of injection-molded containers. Moreover, with packaging containers made from a plastic film, it is often not possible to permanently reclose the corresponding filling openings because they are often only closed by a disposable sealing film which after having been torn off cannot be permanently closed again.